Not that vintage Hollywood movies didn’t have all kinds of social agendas, whether they were about fighting racism (“The Defiant Ones”) or mob justice (“The Ox-Bow Incident”) or anti-Semitism (“Gentlemen’s Agreement”) or war (“All Quiet on the Western Front”). The trick has always been to disguise the heartworm pill of your message with the tasty bologna of drama or satire or whatever else people actually want to see. (John Waters devilishly parodied racial-understanding movies in the trappings of a toe-tapping musical with “Hairspray.”)

Even as late as 1979’s “The China Syndrome,” one of Hollywood’s last great message flicks before made-for-TV films took over the genre, the filmmakers were shrewd enough to make the movie a thriller first and an anti-nuke polemic second. Audiences don’t want to be preached at, but they can be susceptible to whatever the filmmaker wants to tell them so long as said message is couched in entertainment.

While there’s no faulting the talent or good intentions of the people behind “Promised Land,” however, they make the mistake of leaving out the spoonful of sugar, which makes the medicine get stuck in your throat. It’s all message and very little movie.

Director Gus Van Sant and screenwriters-stars Matt Damon and John Krasinski (working from a story by Dave Eggers) want you to know that fracking — the practice of injecting water deep into the earth to extract natural gas — is a very, very, very bad thing, with grave consequences for the environment. But even if you agree with that thesis, as I do, that’s not enough for a narrative film.

The tale, such as it is, involves energy company reps Steve (Damon) and Sue (Frances McDormand) sweeping into a small town to buy up leases from the locals that will allow their bosses to come in and frack the land. Steve has seen small farming communities like this one die out over the course of his lifetime, and he feels like he’s offering the townsfolk a second chance with the money they can make.

Less on-board with all of this is Frank (Hal Holbrook), a wise local elder who knows a thing or two about science and who speaks out against fracking at a town meeting, turning what should have been an open-and-shut deal for Steve and Sue into a complicated matter that will now have to be voted on by the whole town.

While the two energy reps turn on the charm (Sue’s particularly adept at changing her look and demeanor to win over whoever she’s talking to), environmental activist Dustin (Krasinski) turns up with lots of dead-cow pictures, telling everyone about how the frackers came to his town and destroyed the land and the water and the farms.

The best thing that “Promised Land” has to offer, besides McDormand’s wonderfully lived-in performance, is a surprising third-act twist that won’t be revealed here, but the movie essentially boils down to Steve possibly discovering he has a soul and, of much less interest, whether Steve or Dustin will win the heart of local teacher Alice (Rosemarie DeWitt).

If either of those storylines had been fully developed, then maybe “Promised Land” would feel more like a movie and less like a jeremiad. As it is, those who are trying to spread the gospel against fracking will probably get better results screening the documentary “Gasland” to the unconvinced. It may not have attractive Hollywood stars, but you do get to see a bunch of people light their polluted tap water on fire.

Alonso Duralde, TheWrap's lead movie critic, has written about film for Movieline, Salon, MSNBC.com. He also co-hosts the Linoleum Knife podcast and regularly appears on What the Flick?! (The Young Turks Network). Senior Programmer for the Outfest Film Festival in Los Angeles and a pre-screener for the Sundance Film Festival, he is also a consultant for the USA Film Festival/Dallas, where he spent five years as artistic director. A former arts and entertainment editor at the Advocate, he was a regular contributor to "The Rotten Tomatoes Show" on Current. He is the author of two books: "Have Yourself a Movie Little Christmas" (Limelight Editions) and "101 Must-See Movies for Gay Men" (Advocate Books).